顎関節部に発生した chronic expanding hematoma の1例

Abstract

We report a rare case of chronic expanding hematoma(CEH)that formed a mass in the temporomandibular region 15 years after injury. A 37-year-old man presented with a subcutaneous, painless mass in the right preauricular region. He had suffered a blow to the right temporomandibular region during a martial arts match 15 years earlier. From 3 years after the trauma, he noticed a painless, subcutaneous swelling in the right temporomandibular region, which showed repeated enlargement and reduction while growing slowly. An X-ray film of the head revealed pressure resorption of bone in the condylar process of the right mandible. CT showed an ovoid lesion in the masseter muscle lateral to the condylar process of the right mandible. The mass margins showed low signal intensities on T1- and T2-weighted MR images, and the interior of the mass displayed a mixture of high and low signal intensities on T2-weighted images. The clinical diagnosis was a soft tissue tumor arising in the temporomandibular joint. Under general anesthesia, the mass was resected with the surrounding normal tissue. The histopathological diagnosis was CEH. The patient remains free of recurrence 6 years after surgery, without motor impairment of the mandibular joint.It is difficult to diagnose CEH preoperatively; however, this condition should be considered in the presence of a history of surgery or trauma in a patient with a gradually enlarging mass.